1. Reducing Canada's vulnerability to climate change - ESS Towards a water budget for Canada: are reanalyses suitable for the task? Vladimir.Korolevich @nrcan.gc.ca Richard Fernandes, Shusen Wang, Anita Simic, Fanfei Gong, Peter Zelic (NRCan, ESS, CCRS) An Activity within the ESS Climate Change Programme Earth Sciences Sector

2. Reducing Canada's vulnerability to climate change - ESS ET Estimation Approach: Apply observed land surface forcings to validated point model (EALCO) for each 1km grid cell. Requirements: –Satellite Earth Observation data for surface parameters. –Point estimates of ET for calibration and validation. – Validated sub-daily climate forcings over Canada: Precipitation (rain and snow), 2m air temperature, 2m wind speed, 2m specific humidity, surface down welling shortwave and longwave radiation, 2m air pressure

3. Reducing Canada's vulnerability to climate change - ESS Research Question How do model reanalysis forcings compare to in-situ point observations? How does modelled ET differ based on different forcings? For a given forcing dataset, what is the partial contribution of uncertainties for each climate variable to uncertainties in modelled ET?

4. Reducing Canada's vulnerability to climate change - ESS Observed Forcings 1960-1990: Hourly Rain, Snow, Insolation, Air Temp, Specific Humidity, Surface Pressure Mean Annual Precipitation (1961-1990) at CWEEDS stations [mm/year]

5. Reducing Canada's vulnerability to climate change - ESS Reanalysis Forcings Anomalies Station longitude (deg E)

6. Reducing Canada's vulnerability to climate change - ESS Reference Annual ET based on Observed Forcings (1980-1990). [mm/year]

7. Reducing Canada's vulnerability to climate change - ESS ET Anomalies *) CRU = Climatic Research Unit, East Anglia UK, 0.5 degree gridded observations

8. Reducing Canada's vulnerability to climate change - ESS Partial Contributions to ET Anomalies

9. Reducing Canada's vulnerability to climate change - ESS Conclusions GR2 and NARR have similar annual biases to station observations. Downwelling radiation bias is substantial and needs more investigation as to timing and causes. GR2 and NARR provide reasonable ET estimates compared to ET based on observations except over Rockies. “PRISM” type precip downscaling in NARR over Canada may substantially improve ET ET estimates in Canadian Rockies Local calibration of either reanalysis forcings or reanalysis driven ET may be desirable if possible. Renalysis forcings offer promise for driving water budget models over remote areas in Canada.

10. Reducing Canada's vulnerability to climate change - ESS. THANK YOU